Is this considered a nuisance?

It's really kind of you to think about contributing to sales. However, since the next customer might be looking forward to it, it might be safest to ask the store staff first and then buy little by little.

It's better for the store if it sells out within the sales period, so there's no problem for them 😀 If it's a large quantity or a wide variety, you could also consider reserving with a store you frequent and asking them to fry it for you. In that case, please try not to overlap too much with the pickup time. This is so they can fry it according to that time and give it to you as fresh as possible. Cancellations are mostly not allowed for large quantities. Payment methods like upfront or post-payment vary by store, so please check when ordering.